Riparian Zone was modelled for the ACT, building on an ACT Government funded project (Johnston et al 2017) monitoring distribution of the two most extensive wooded riparian vegetation communities in the ACT - River She-oak (Casuarina cunninghamiana) riparian forest (p32d) and Ribbon Gum (Eucalyptus viminalis) very tall woodland (p520).

As this work is primarily based around Murrumbidgee River and Molonglo River, a decision rule-set was used to model riparian areas elsewhere in the ACT. This layer was created by merging the below input layers and intersecting with the Catchment Management Zones layer, so that features may be identified according to the relevant management area.

Input Layers:

• RiparianZone4_u52SLOPE10

  • Riparian Zone along major watercourses (i.e. Murrumbidgee, Cotter and Molonglo Rivers) was delineated manually based on visual assessment of aerial imagery and taking into account areas identified as 'riparian' by Johnston et al (2017). Edge of the riparian zone was identified by a clear contrast betweeen streambank vegetation communities (incl. areas of rock or sand) and the surrounding landscape. In areas where the vegetation appeared continuous on either side and across a watercourse, there was deemed to be no visible riparian zone.

  • This layer also incorporates areas identified in the ACT Vegetation Map as containing riparian vegetation communities. These riparian communities are identified in the CEMP Aquatic and Riparian monitoring planand include: Ribbon Gum very tall woodland (p520); River She-oak riparian forest (p32d); rocky riparian tall shrubland (u181); tableland aquatic and fringing vegetation complex (AFV); wet tussock grassland (r2)/

  • Upland Grassland communities (i.e. a14, a2, a9, e59, r1, u193) were excluded from the modelled riparian zone as these vegetation communities will be addressed in the CEMP Upland Grassland monitoring plan.

  • In order to account for the prevalence of vegetation community u52on shaded or moist hillslopes outside the riparian zone, a slope threshold was applied to this vegetation community alone. Areas greater than 10* slope are considered to be non-riparian.

• WATERBODY4_BUFF5

  • This layer represents a combination of waterbodies located in the ACT represented in the following spatial datasets available on the CGD: CGDMGA_URBAN_LAKE_POND; Reserve_dams_12; CGD.INLAND_WATER_AREA; All_water_polygons

  • Ponds, dams and wetlands were subsequently selected from these layers. Waterbodies excluded include rivers or creeks as these are captured already, and swamp areas as these will be addressed in the upland CEMP monitoring plans. A buffer of 5 metres was applied to all selected waterbodies to take into account the potential for a riparian zone.

• SO1234BUFF_byCMZ

  • Based on a visual assessment of the width of riparian areas, a buffer was applied to the LPI_Drain_1yr stream network according to stream order: Stream Order (SO) 1 = 7.5m; SO2 = 10.0m; SO3 = 15.0m; SO4 = 20.0m. Note that riparian areas bordering all fifth-order streams in the ACT were assessed manually as described above.

Projected coordinate system: GDA_1994_MGA_Zone55